1. Field of the Invention
The present invention relates to the preparation of cyanomethyl esters by reacting a carboxylic acid halide with an alpha-hydroxynitrile in the presence of certain amines and a minor amount of water impurity.
2. State of the Art
It is known to prepare cyanomethyl esters by reacting a carboxylic acid halide with an alpha-hydroxynitrile in the presence of a molar excess of a tertiary amine hydrogen halide acceptor. However, when this reaction is conducted in the presence of minor amounts of water (usually present as impurities in one or more of the ingredients of the reaction), technical difficulties and an unsatisfactorily impure product cyanomethyl ester can arise because free carboxylic acid is formed which then reacts with the carboxylic acid halide to form a relatively unreactive carboxylic acid anhydride byproduct, thereby reducing the yield of desired cyanomethyl ester, which is also contaminated by the byproduct anhydride. The anhydride is not readily removed from the ester by simple conventional procedures, such as extraction or distillation. Thus, it is highly desirable to eliminate this anhydride from the product produced in the presence of water.